1. Field of the Invention
The present invention relates to fluoroalkyl functional group containing organopolysiloxane-containing compositions based on water/ alcohol, to a process for their preparation and to their use.
2. Description of the Background
Organosilanes of the formula R'-Si(R").sub.3, wherein R' is a fluorinated organic radical and R" is a chlorine, methoxy or ethoxy radical, have diverse uses, for example for application of hydrophobically and oleophobically acting layers to surfaces.
It is known that oil- and water-repellent coatings on surfaces, usually glass surfaces, are produced with the aid of fluoroalkylalkoxysilanes and fluoroalkylchlorosilanes. The coatings can be used, for example, to provide plate glass with a dirt-repellent treatment. The processes described are based on sol-gel processes, very fine inorganic particles being produced and employed together with the fluoroalkylsilane. The application of such systems is technically demanding and usually uses complex organic solvent mixtures and additives (European Laid-Open Application No. 0 658 525 and European Laid-Open Application No. 0 629 673).
Large amounts of organic solvents are also employed for the production of oil and water-repellent coatings; for example, an ethanol content of 52% by weight is used in formulations shown in U.S. Pat. No. 5,424,130.
In the processes described, the complicated application processes, on the one hand, and the use of organic solvents, on the other hand, have adverse effects. In some processes, even substances which are very problematic ecologically such as chlorinated hydrocarbons or fluorohydrocarbons, are employed as solvent in a considerable concentration (European Laid-Open Application No. 0 491 251 and European Laid-Open Application No. 0 493 747). A need continues to exist for aqueous based solutions of organosilanes which provide water and oil resistant coatings.